What happens during a solar panel installation
A solar panel installation involves mounting panels to your roof, running electrical wiring through your home, connecting an inverter that converts DC power to AC power, and tying the system to your electrical panel and the grid. The work typically takes three to five days for a residential system, though the timeline depends on your roof size, complexity, and local permitting.
Most homeowners hire a licensed solar contractor to do this work rather than attempting it themselves. The contractor handles design, permitting, installation, and inspection. You will need to decide whether to buy the system outright, finance it through a loan, or lease it from the installer — each option affects your costs and long-term savings differently.
Key Takeaways
- Your roof must be structurally sound and have 10 to 15 years of remaining lifespan before installation, because removing panels to repair the roof later is expensive.
- A solar contractor will assess your roof's angle, shading, and condition during a site visit before giving you a price quote.
- Installation requires local building permits and electrical inspections; the contractor usually handles these, but you pay the fees.
- The entire process from quote to grid connection typically takes two to four months, depending on your area's permitting speed.
- You will need to decide between buying the system outright, taking a loan, or leasing before signing a contract.
Assessing whether your roof is suitable
Before any installation can happen, a contractor needs to inspect your roof in person. They will check the roof's age, material, structural integrity, and remaining lifespan. Most installers will not put panels on a roof with fewer than 10 to 15 years of life left, because removing and reinstalling panels during a roof replacement costs thousands of dollars.
The contractor will also measure the roof's angle and orientation. South-facing roofs in the Northern Hemisphere receive the most sunlight and produce the most power. East or west-facing roofs work but produce less. The roof's pitch (steepness) affects how the panels sit; most systems work on pitches between 15 and 40 degrees, though flat roofs can accommodate panels with special mounting hardware.
Shading from trees, chimneys, or nearby buildings reduces output significantly. The contractor will use tools to map shade patterns throughout the day and across seasons. If your roof is heavily shaded, solar may not be cost-effective, or you may need fewer panels than a fully sunny roof would support.
Getting a quote and understanding the costs
Contact three to five solar contractors in your area and request a free site visit and quote. The contractor will assess your roof, review your electricity bills to understand your usage, and design a system sized to meet your needs. The quote will show the system size in kilowatts, the estimated annual output, the total cost, and the estimated payback period.
Costs vary widely by region, installer, and system size. A typical residential system ranges from $15,000 to $25,000 before any tax credits or incentives. Your actual out-of-pocket cost depends on how you pay: buying outright, financing with a loan, or leasing. A federal tax credit currently covers 30 percent of the system cost if you own it; leased systems do not may have access to for this credit, but the lease payment is often lower upfront.
Ask each contractor about local and state incentives, rebates, and tax credits you may be able to use. These vary by location and change year to year. The contractor should include any available incentives in their quote.
Permits, inspections, and timeline
Once you sign a contract, the contractor submits permit applications to your local building department. This step takes anywhere from one week to two months depending on how quickly your jurisdiction processes applications. You will pay permit fees, which typically range from $200 to $500.
After permits are approved, the contractor schedules the installation. The actual roof work takes two to five days. Once panels are installed and wired, a city or county inspector must visit to verify the electrical work meets code. This inspection usually happens within one to three weeks of installation completion.
After inspection approval, the contractor coordinates with your utility company to set up grid connection. This final step can take another two to four weeks. Until grid connection is complete, your system will not produce power to your home or send excess power back to the grid.
What happens during the actual installation day
On installation day, the crew will arrive early and set up safety equipment and staging areas. They will mount the racking system (metal frame) to your roof using bolts that penetrate the roof and attach to the home's structure. The panels then bolt to the racking. This part takes most of the first day.
On subsequent days, the crew runs electrical conduit and wiring from the roof panels down through your home to the inverter, usually located in a garage, basement, or utility room. They connect the inverter to your main electrical panel and install a disconnect switch that lets you shut down the system safely. All wiring must meet National Electrical Code standards.
The crew will also install monitoring equipment that tracks how much power your system produces. You will be able to see real-time output on your phone or computer after set up. Before leaving, the contractor will walk you through how to use the monitoring app and what to expect from your system.
Roof penetrations and weatherproofing
The racking system requires bolts through your roof, which creates penetration points. Proper sealing is critical to prevent leaks. Licensed installers use flashing — metal or rubber seals that fit around the bolts — and roofing cement or sealant to waterproof each penetration. This work should be done carefully and inspected during the city inspection.
If your roof is relatively new and in good condition, these penetrations should not cause problems if sealed correctly. If your roof is older or already has minor leaks, the installation crew may recommend addressing those issues before panels go on. Some contractors will not install on roofs they consider too compromised.
Maintenance and what to expect after installation
Solar panels require very little maintenance. You may need to rinse them with a hose once or twice a year if you live in a dusty area or if bird droppings accumulate. Most systems have no moving parts and no regular servicing needed.
The inverter typically lasts 10 to 15 years and may need replacement during the system's 25 to 30 year lifespan. Panels themselves degrade slowly — they produce about 80 percent of their original output after 25 years. Your monitoring system will alert you if output drops unexpectedly, which usually signals a wiring problem or equipment failure.
If you own the system, you are responsible for repairs and replacement costs after the manufacturer's warranty expires. If you lease, the leasing company handles maintenance and repairs. This is one reason some homeowners prefer leasing despite missing out on tax credits.
Frequently Asked Questions
Do I need to replace my roof before installing solar panels?
Only if your roof has fewer than 10 to 15 years of life remaining. The contractor will assess this during the site visit. If replacement is needed soon, it is usually cheaper to do it before panels go on rather than remove panels later to access the roof.
What if my roof is not south-facing?
East or west-facing roofs work but produce 15 to 25 percent less power than a south-facing roof. The contractor will design a system accounting for this reduced output. If your roof is north-facing or heavily shaded, solar may not be economical.
How long does the whole process take from first call to power generation?
Typically two to four months. This includes the site visit and quote (one to two weeks), permit approval (one to eight weeks depending on your area), installation (three to five days), inspection (one to three weeks), and grid set up (two to four weeks).
What happens if I sell my house after installing solar?
If you own the system, it transfers with the home and adds to the property value. If you lease, you must either transfer the lease to the new owner or pay a buyout fee. Ask your contractor about their transfer policy before signing a lease.
Can I install panels myself to save money?
Rooftop solar installation involves electrical work, structural modifications, and code compliance that require licensed professionals in most jurisdictions. Attempting this yourself voids manufacturer warranties, creates safety hazards, and will not pass inspection. Hiring a licensed contractor is the standard approach.